DC VOLTAGE GRID WITH VARIABLE VOLTAGE

Abstract

A DC voltage grid includes an electrical conductor electrically interconnecting electrical components, with a DC voltage applied between parts of the electrical conductor. An actuator is configured to vary the DC voltage such that a value of the DC voltage depends on at least one state of the DC voltage grid. Information about the at least one state is transmitted to the electrical components of the DC voltage grid by way of the DC voltage. A wind farm having wind turbines connected to such a DC voltage grid and a method for operating such a DC voltage grid or such a wind farm are also disclosed. The DC voltage of the DC voltage grid is controlled or regulated depending on a state of the DC voltage grid.

Claims

1.-15. (canceled)

16. A DC voltage grid, comprising: an electrical conductor electrically interconnecting electrical components and having a DC voltage applied between parts of the electrical conductor; and an actuator configured to vary the DC voltage such that a value of the DC voltage depends on at least one state of the DC voltage grid, wherein information about the at least one state is transmitted to the electrical components of the DC voltage grid by way of the DC voltage.

17. The DC voltage grid of claim 16, wherein one of the electrical components is a protective device of the DC voltage grid.

18. The DC voltage grid of claim 17, wherein the protective device is arranged at a distance of more than 10 m from others of the interconnected electrical components.

19. The DC voltage grid of claim 17, wherein the protective device is arranged at a distance of more than 100 m from others of the interconnected electrical components.

20. The DC voltage grid of claim 16, wherein the electrical components comprise an energy storage unit and an electrical consumer.

21. The DC voltage grid of claim 16, wherein at least some of the electrical components comprise energy sources in form of wind turbines configured for blade adjustment as a function of the value of the DC voltage.

22. A wind farm comprising a DC voltage grid with an electrical conductor electrically interconnecting electrical components and having parts between which a DC voltage is applied, and with an actuator configured to vary the DC voltage such that a value of the DC voltage depends on at least one state of the DC voltage grid and information about the at least one state is transmitted to the electrical components of the DC voltage grid by way of the DC voltage, wherein at least some of the electrical components comprise energy sources in form of wind turbines configured for blade adjustment as a function of the value of the DC voltage.

23. A method for operating a DC voltage grid or a wind farm connected to the DC voltage grid, wherein the DC voltage grid has an electrical conductor electrically interconnecting electrical components and a DC voltage is applied between parts of the electrical conductor, the method comprising controlling or regulating a value of the DC voltage as a function of a state of the DC voltage grid, and transmitting information about the state of the DC voltage grid to the electrical components by way of the DC voltage.

24. The method of claim 23, further comprising changing an operating behavior of at least some of the electrical components as a function of the value of the DC voltage.

25. The method of claim 23, further comprising increasing the DC voltage of an energy storage unit that is part of the interconnected electrical components as a state of charge (SoC) of the energy storage unit increases.

26. The method of claim 23, further comprising increasing the DC voltage of an energy source that is part of the interconnected electrical components as the capacity utilization of the energy source decreases.

27. The method of claim 26, wherein the energy source is a wind turbine.

28. The method of claim 23, wherein several of the interconnected electrical components comprise energy sources and at least a portion of the energy sources are deactivated when a first threshold value is exceeded.

29. The method of claim 23, wherein several of the interconnected electrical components comprise energy storage units and at least a portion of the energy storage units are discharged when a second threshold value is exceeded.

30. The method of claim 23, wherein several of the interconnected electrical components comprise electrical consumers and at least a portion of the electrical consumers are operated with reduced power or deactivated when a third threshold value is undershot.

31. The method of claim 23, wherein one of the electrical components is a protective device of the DC voltage grid, the method further comprising activating the protective device when a safety threshold value of the DC voltage is exceeded or undershot.

32. The method of claim 27, further comprising adjusting blades of the wind turbine as a function of the value of the DC voltage.

Description

[0028] The invention is described and explained in more detail below on the basis of the exemplary embodiments shown in the figures, in which:

[0029] FIG. 1 shows a DC voltage grid,

[0030] FIG. 2 shows the relationship between the state of charge of the energy storage unit and a first voltage adjustment factor, and

[0031] FIG. 3 shows the relationship between the capacity utilization of the energy sources and a second voltage adjustment factor.

[0032] FIG. 1 shows an exemplary embodiment of a DC voltage grid 1. This has one or several energy sources 3, and electrical consumers 5. In addition, the DC voltage grid 1 can also have energy storage units 4 and a protective device 7. The DC voltage U.sub.1 of the DC voltage grid 1 is variable and is present between the two parts 61, 62 of the conductor 6, which interconnects the individual electrical components 3, 4, 5, 7. This DC voltage U.sub.1 can be adjusted, in other words varied, by the actuator 2 in order to describe the state of the DC voltage grid 1. The actuator 2 is fed from a voltage source 10 with a voltage U.sub.2. The voltage source is an energy source which specifies the DC voltage U.sub.1 in the DC voltage grid 1 via the actuator 2. This voltage source 10 can be formed for example by a power supply network from which energy is drawn to feed the electrical consumers 5 or into which energy from wind turbines is fed. It can also be a generator of a vehicle.

[0033] FIG. 2 shows a diagram for the adjustment of the DC voltage U.sub.1 as a function of the state of charge SoC of the energy storage unit 4. The fuller the energy storage unit 4, the higher the first voltage increase factor α. The DC voltage U.sub.1 is calculated by multiplying the voltage U.sub.2 of the voltage source 10 by the first voltage adjustment factor α as follows:

U.sub.1=U.sub.2.Math.α.

[0034] Here, the relationship between the state of charge SoC and the first voltage adjustment factor α can be linear, but can also be formed by any other monotonic function.

[0035] FIG. 3 shows a diagram for the adjustment of the DC voltage U.sub.1 as a function of the capacity utilization a of the energy sources 3. The lower the capacity utilization of the energy sources, the higher the second voltage increase factor β. The DC voltage U.sub.1 is calculated by multiplying the voltage U.sub.2 of the voltage source 10 by the second voltage adjustment factor β as follows:

U.sub.1=U.sub.2.Math.β.

[0036] Here, the relationship between the capacity utilization a and the second voltage adjustment factor β can be linear, but can also be formed by any other monotonic function. It can be advantageous here if the second voltage adjustment factor β is constant over a certain range of the capacity utilization a.

[0037] If both a first and a second voltage adjustment factor is used by including the state of charge SoC and the capacity utilization a, then the DC voltage U.sub.1 is calculated by multiplying the voltage U.sub.2 of the voltage source 10 by the first voltage adjustment factor α and the second voltage adjustment factor β as follows:

U.sub.1=U.sub.2.Math.α.Math.β.

[0038] The individual values α.sub.1, α.sub.2, β.sub.1, β.sub.2 of the first and second voltage adjustment factor result from the configuration of the DC voltage grid 1. It is necessary to consider here that the values α.sub.1, α.sub.2, β.sub.1, β.sub.2 do not cause an overloading of the DC voltage grid 1 in terms of voltage or current.

[0039] In summary, the invention relates to a DC voltage grid, wherein the DC voltage grid is able to be operated with a DC voltage. To improve the DC voltage grid, it is proposed for the DC voltage grid to have an actuator by way of which the DC voltage of the DC voltage grid is able to be varied, wherein the amount of the DC voltage depends on the state of the energy sources and/or of the energy storage units and/or the electrical consumers. The invention furthermore relates to a method for operating such a DC voltage grid, wherein the DC voltage of the DC voltage grid is controlled or regulated as a function of the state of the energy sources and/or of the energy storage units and/or of the electrical consumers.

[0040] In other words, the invention relates to a DC voltage grid having electrical components which are interconnected electrically by means of a conductor, wherein the DC voltage grid is able to be operated with a DC voltage between parts of the conductor. To improve the DC voltage grid, it is proposed for the DC voltage grid to have an actuator by way of which the DC voltage of the DC voltage grid is able to be varied such that the value of the DC voltage depends on at least one state of the DC voltage grid and information about the state is transmitted to the electrical components of the DC voltage grid by way of the DC voltage. The invention furthermore relates to a wind farm having such a DC voltage grid with wind turbines. The invention furthermore relates to a method for operating such a DC voltage grid or such a wind farm, wherein the DC voltage of the DC voltage grid is controlled or regulated as a function of a state of the DC voltage grid.